Fluid supply system



May 31, 1966 Original Filed Nov. 29, 1963 G. w. JACKSON 3,253,775

FLUID SUPPLY SYS TEM 5 Sheets-Sheet l IN VEN TOR.

aarye dd. Jackron BY V FLUID SUPPLY SYSTEM Original Filed Nov. 29, 19635 Sheets-Sheet 2 i z a? w /6% I #2 /6'0 l0 4% l M w 7 I. a w 7 441% I! HM I INVENTOR- Gearqe 14 Jae/ son 60 w 74 6 my ATTOR/Viy May 31, 1966 cs.w. JACKSON 3,253,775

FLUID SUPPLY SYSTEM Original Filed Nov. 29, 1963 5 Sheets-Sheet 5INVENTOR.

H1) ATTORNEY United States Patent 3,253,775 FLUID SUPPLY SYSTEM GeorgeW. Jackson, Dayton, Ohio, assignor to General Motors Corporation,Detroit, Mich., a corporation of Delaware Original application Nov. 29,1963, Ser. No. 327,008. Divided and this application Mar. 30, 1965, Ser.No. 444,017

6 Claims. (Cl. 230-52) This application is a division of applicationSerial No. 327,008, filed November 29, 1963.

This invention relates to an improved pressurized fluid supply systemfor association with an air lift suspension system or the like.

In many present-day pressure actuated systems, for example, the air liftsuspension system of an automobile or the like, there is a definite needfor a low-cost, compactly arranged pressurized fluid supply system thatis reliable and positive acting under a wide variety of operatingconditions. While various arrangements of this type have been proposed,no single system has been completely satisfactory. i

An object of the present invention, therefore, is to provide a highlyefficient, positive pressure supply system.

for association with a pressure actuated device, for example, an airlift spring component of an air lift suspension system including theprovision of an improved combination pump-reservoir structure havingcompact dimensional characteristics suited for location in a space orcompartment of limited dimensions in a motor vehicle or the like.

A further object of the present invention is to provide such acombination pump-reservoir structure including improved means forminimizing noise transfer from the operating pump structure to thepassenger compartment of a vehicle associated therewith.

A further object of the present invention is to improve means forsupplying a pressurized fluid to a pressure actuated device by theprovision of a combination reservoir and pump assembly wherein a portionof the pump is supported on the reservoir to serve as one wall of thepressure reservoir and to further serve as one of the walls of the pumpcasing with the pump further being characterized by a pair of axiallyaligned pistons therein interconnected by a piston rod operativelyassociated with a diaphragm for reciprocation within a pair of axiallyspaced cylinders that are aligned with the pistons wherein the flow ofpressurized fluid proceeds from the first compression cylinder throughan axially directed passageway through the piston rod and thence throughthe second stage compression chamber and an outlet therefrom into saidreservoir under the control of a valving arrangement that lends itselfto economical mass production.

A still further object of the present invention is to provide animproved compactly arranged pressurized fluid supply system includingthe provision of a reservoir formed in part by a part of the housing ofan improved two-stage diaphragm operated compressor including theprovision of a diaphragm actuated selector valve arrangement foralternately directing atmospheric and subatmospheric pressure sources toeither side of an imperforate operating diaphragm for producingreciprocating movement thereof to drive piston portions of the pumpwithin cylinders to effect the multiple-stage compression, wherein theselector valve arrangement is characterized firstly by a minimalconsumption of limited diaphragm motive power in assuming alternatefluid controlling positions and secondly by substantially noiselessoperation.

Further objects and advantages of the present invention will be apparentfrom the following description, refer- 3,253,775 Patented May 31, 1966ence being had to the accompanying drawings wherein a preferredembodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a view in side elevation of a vehicle suspension includingthe pressurized fluid supply system of the present invention;

FIGURE 2 is a view in vertical section taken along the line 22 of FIGURE1;

FIGURE 3 is an enlarged view in side elevation of the improvedpressurized fluid supply system;

FIGURE 4 is a fragmentary, enlarged view in end elevation looking in thedirection of arrow 4 in FIG- URE 3;

FIGURE 5 is a view in vertical section taken along the line 55 of FIGURE4;

FIGURE 6 is a view in horizontal section taken along the line 6-6 ofFIGURE 4; and

FIGURE 7 is a reduced sectional view taken along the,

line 77 of FIGURE 6. p

In FIGURES 1 and 2 of the drawings, a vehicle 10 is illustrated asincluding a sprung assembly comprising a chassis frame 12 having a body14 supported thereon along with conventional parts normally associatedthere- .with and further including an unsprung assembly comprisingground engaging wheels 16 supported on an axle housing 18 in aconventional manner along with other parts normally associated with suchwheels and housings. The sprung assembly represented by the chassisframe 12 and body 14 is supported relative to the axle housing 18 of theunsprung assembly by means representatively illustrated as including apair of control arms 22 each having one of its ends pivotally secured toa bracket 24 fixed to the suspended chassis frame 12. Each control arm22 is also fixedly secured adjacent its opposite end to the axle housing18 through a bracket 26 to thereby serve as a support for one of a pairof coil type chassis springs 28 mounted between the control arms 22 andthe frame 12 for providing a desired spring support between sprung andunsprung masses. In addition to the supporting action of each coil typechassis spring 28, additional .ride control is provided by a pair ofshock absorber and air spring auxiliary suspension units 29,respectively, pivotally secured at the opposite end of one or the otherof control arms 22 and the frame 12.

Details of a typical combination shock absorber and air spring auxiilarysuspension unit 29 are more particularly set forth in the United StatesPatent 3,042,392 issued July 3, 1962, to Schmitz et al., with it beingunderstood that each of the auxiliary units 29 basically includes adirect-acting hydraulic shock absorber 30 having an inflatable elementor air spring 31 thereon of a suitable resilient material that, wheninflated, will supplement the load carrying capacity of the coil springs28 so as to prevent excessive engagement of bump stops on the vehicleand/or an undue elevation of the front end. of the vehicle when heavyloads are placed in the body 14 in the vicinity of the axle housing 18.The above-described system, of course, is merely representative, itbeing understood that the improved features of the pressurized fluidsupply system of the present invention are equallywell suited forassociation with arrangements having pressure actuated componentsequivalent to air springs 31. Referring now to FIGURES 3 through 7, apressurized fluid system 32 is illustrated including an elongatedcylin-' drical pressure reservoir 34 having a closed end 36 and an openend 38 that has a ring-like reinforcing bracket 40 connected thereto forsupportingly receiving an outwardly directed flange 42 on a firsthousing portion 44 of a vacuum operated pump 46. Between the bracket 40and- 3 flange 42, as best shown in FIGURE 5, an annular sealing element48 of resilient material is located in sealing engagement there'betweento prevent fluid leakage outwardly at the open end 38 of reservoir 34.

In the illustrated arrangement, the housing portion 44 has a passageway50 directed therethrough intercommunicating the interior of thereservoir 34 with a control valve assembly 52 controlling flow ofpressurized fluid from the reservoir 34 through a conduit 54 intercornmunicating the interior of the valve 52 with fluid lines 56 running toeach of the air springs 31 of the auxiliary units 29. For purposes ofthis application, it is only necessary to point out that the controlvalve is a type that can be manually controlled by means of a Bowdenwire actuator assembly 58 located conveniently to an operator of thevehicle, for example, on the dashboard where it is selectively operableto condition the valve 52 to either communicate the auxiliary suspensionunit 29 with pressurized fluid within the reservoir 34 or withatmosphere depending upon whether or not it is desired to ob tain asupplemental supporting action to that of springs 20. For a moredetailed explanation of valve 52, reference is made to copending UnitedStates application, Serial No. 327,008, filed November 29, 1963, ofGeorge W. Jackson for Control Valve, with it being understood that theJackson valve is only representative of many control valves that wouldbe suited for controlling flow of fluid between the system of thepresent invention and a pressure actuated device associated therewith.Referring now particularly to pump 46 in FIGURES 4-7, an economical,compact, two-stage compressor arrangement is illustrated as including asecond housing portion 60 joined to the first housing portion 44 and tothe bracket 40 on the reservoir 34 by a plurality of circumferentiallylocated stud and nut fasteners 62. Certain of the nuts on fasteners 62are formed to serve as a means for threadably fastening a plurality oftubular damping pads 64 on the pump 46. A like pad 66 is secured to theclosed end of reservoir 32 exteriorly thereof to cooperate with pads 64to prevent transmission of vibrations from the improved system to itssupporting framework.

The pump 46 is further characterized by the fact that housing portion 44has a hollow cylindrical extension 70 thereon directed interiorly of thereservoir 34 in axial alignment with a somewhat larger diameter hollowcylindrical extension 72 on housing part 60- extending oppositely toextension 70. In the ilustrated embodiment, the cylindrical extension 70is opened at the outer end thereof and the cylindrical extension 72 isclosed at the outer end thereof.

The joined housing portions 44, 60 more particularly define -a space orchamber intermediate the cylindrical extensions 70, 72 divided into afirst and a second compartment 74, 76 by a centrally apertured, flexiblediaphragm element 78 located within and directed transversely of thepump housing chamber where the outer periphery of the diaphragm 78 is injuxtaposition with the outer periphery of both housing portions 44, 60at the juncture thereof being held in sealing engagement therewith bythe screw and nut fasteners 62. Ring-shaped reinforcing discs 80, 82 arelocated on either face of the diaphragm 78 so that the central openingstherethrough are concentric one with the other to receive an elongatedpiston rod 86 extending substantially centrally of and axially throughcompartments 74, 76.

The elongated piston rod 86 more particularly includes a radial-1youtwardly directed shoulder portion 88 thereon located intermediate theends thereof having one face thereof located in axial abutment with thedisc 80 to cooper-ate with an annular snap ring element 98 on rod 86that is biased against the disc '82 to hold the diaphragm 78 in sealingengagement with the rod 86 and discs 80, 82 at the interfacestherebetween to thereby seal against fluid flow between compartments 74,76.

One end 91 of the rod 86 supports an annular channelshaped sealingelement 92 that sealingly engages the inner surface of the cylindricalextension when held in place by an annular filler Washer 94 in anannular recess 96 in the outer surface of the end of rod 86. A likerecess 98 spaced axially inwardly of recess 96 supports an annularwasher 100 of a suitable porous material, for example, felt, that isimpregnated with a suitable lubricant for reducing sliding frictionbetween the outer periphery of the end of rod 86 and the inner surfaceof extension 70.

The opposite end 102 of the rod 86 is of a somewhat larger diameter thanend 9 1 and supports an annular channel-shaped sealing element 104 andannular lubricating washer 106 in recesses 108, 110 in the outerperiphery thereof serving the same function as elements 92, 100 on theend 91. The end 102 further includes a plurality of circum-ferentiallyspaced passageways 112 directed therethrough for intercommunicatingcompartment 76 with the interior of cylindrical extension 7 2. On theend face of piston rod end 102 an annular valving element 114 of asuitable resilient material is supported to extend radially outwardlyfrom adjacent the central axis of rod 86 so that a free edge thereofoverlies the ends of passageways 112. The valving element 114 therebyserves as a means for checking fluid flow from the interior of extension72 into compartment 76 while allowing substantially free fluid flow fromthe compartment 76 into the interior of cylinder 72 prior to first-stagecompression. A check valve element 116 supported within the opposite end91 of the piston rod 86 is biased into a seated position by a spring 118to control flow of first-stage compressed fluid through an axial opening119 directed centrally through the piston rod 86 for communicating theinterior of extension 72 with the interior of extension 70 and a checkvalve 120 supported within a small diameter interior end space 122 incylindrical extension 70 is biased closed by spring 124 to controlsecond-stage compressed fluid flow 'from pump 46 into reservoir 34.

By virtue of the provision of valving elements of the aforedescribedtype in association with a reciprocating diaphragm actuated piston rod,a multiple-stage compression of a fluid such as air can be accomplishedby a limitedpressure differential such as established by the vacuumsystem of an automobile acting alternatively on opposite sides of theflexible diaphragm 78 under the control of an improved selector valveassembly 1125.

The fluid flow in the illustrated embodiment of the improved compactlyarranged pressurized fluid supply system includes the passage of fluidinto compartment 76 from valve 125 and from the compartment 76 acrossthe passageways 112 in piston end 102 upon reciprocation of piston rod86 inwardly of cylindrical extension '70 and exteriorly of cylindricalextension 72 and thence past the free edge of annular valving element114 which is moved out of axial abutment with the end of the piston 102during such movement and thence into the progressively increasinginterior space of cylindrical extension 72. Following a predeterminedstroke during which time the interior space of cylindrical extension 72has progressed to a predetermined maximum volume, the piston rod 86 willbe reciprocated in an opposite direction by changing the connectionbetween compartment-s 74, 76 on opposite sides of diaphragm 78 and highand low pressure systems. During the opposite reciprocation of pistonrod H 86 by diaphragm 78, the piston rod moves exteriorly of cylindricalextension 70' and interiorly of'cylindrical extension 72 so that fluidwithin the progressively diminising interior space of extension 72 isforced therefrom axially through the passageway 119 to produce apressure differential across the check valve element 116 sufficient tomove it against the action of spring 118 sufflciently to allowfirst-stage compressed fluid to flow interiorly of the progressivelyincreasing interior space of cylindrical extension 70. During thisopposite reciprocation of piston rod 86 the valving element 114 isbiased by the pressure buildup within the-interior space of cylindricalextension 72 against the passageways 112 communicating compartment 76and the interior of cylindrical extension 72 to thereby prevent fluidleakage into the compartment 76 which is evacuated during such oppositereciprocation in a manner to be discussed. Upon reciprocation of thepiston rod 86 in the first mentioned direction the first-stagecompressed fluid in the interior space'of cylindrical extension 70 isfurther compressed by movement of the piston end 91 inwardly thereofwith the compressed fluid producing a pressure differential across thecheck valve element 120 sufficient to move it against the biasing actionof spring 124 to thereby communicate the interior of reservoir 34 withthe interior of cylindrical extension 70.

The improved valving arrangement for producing the aforementionedcontrolled two-stage compression lends itself to economical massproduction methods of assembly and also includes the additional featureof elements at each end of the piston rod that materially reducefrictional losses in the operating device to thereby improve theefliciency thereof by maximizing output pressure capability of thelimited pressure differential across the diaphragm 78.

In addition to the reduced friction at the interface between the pistonrod end portions and the cylindrical extensions 70, 72 and the inherentreduced frictional losses of the diaphragm 78, the rod driven selectorvalve assembly 125 that alternately connects the compartment 74, 76 witha vacuum or atmospheric source for effecting the opposite reciprocationof rod 86 is constructed and arranged so as to operate withoutmaterially affecting the efliciency of the compressor portion of thesystem.

More particularly, the selector valve assembly 125 is representativelyshown as being associated with a first port 126 in-housing portion 60adapted to be connected through a conduit (not shown) with a source ofvacuum or subatmospheric pressure, such as the vacuum manifold on theinternal combustion engine of an automobile vehicle. The housing portion60 is also provided with two ports 127, 128 positioned equidistantly oneach side of the vacuum port 126, port 127 communicating compartment 74With atmosphere through a port extension 130 formed in the housingportion 44 as best illustrated in FIGURE 7.

The housing portion 60 has a planar face 132 on the exterior thereof atthe ports 126, 127, 128 on which a valving element 134 is pivotallysecured by a screw element 136 directed through a sleeve bearing 138inserted in element 134 at one end thereof into threaded engagement withthe housing portion 60. The sleeve bearing 138 is preferably constructedof a low coefiicient of friction material from a grouping of materialsset forth in greater detail subsequently. The opposite end of thevalving element 134 has an arcuately-shaped passageway 139 thereinhaving a portion thereof overlying the vacuum port 126 in face 132 andother portions thereof alternately overlying the ports 127,128 uponlimited rotation of the valving element 134 about the pivot pointdefined by screw element 136 as produced by an actuating linkageassembly 140 of the selector valve assembly to thereby serve toselectively intercommunicate the compartments with atmosphere and avacuum source so as to cause diaphragm 78 to reciprocate piston rod 86.One feature of valve 125 is that ports 126, 127, 128 aretrapezoidally-shaped to require less valve travel in the selectingprocess.

The valving element 134 is constructed of a plastic material withrelatively low coefficient of friction and resilient properties such asare found in the representative of adapted to be engaged by the surfaceon piston rod shoulder 88 that faces the large diameter piston end 102.The crank arm 146 has the opposite end thereof secured by a pin 147 toone end 148 of a bent swivel arm 150, the end 148 being rotatablysupported in sleeve bearings 152, 154 supported in a protuberance 155 onthe housing portion 60 located radially inwardly thereon group includingZytel, a nylon resin; Alathon, a polyfrom the valving element 134. Thesleeve bearings 152, 154, like bearing 138 and valving element 134, areconstructed of a low coefficient of friction plastic material of thetype discussed above for reducing frictional losses caused by rotationof the end 148 of swivel arm by crank arm 146. Opposite end 156 of thebent swivel arm 150 is offset ninety degrees from end 148 and directedthrough an opening 158 in an elongated cantilevered actuating arm 160having one end thereof pivotally secured on the axially outermostportion of protuberance by a screw element 162 directed therethroughinto threaded engagement with the housing portion 60. In order tominimize galling of arm 150 by arm a hemispherically-shaped bearingsurface 165 is formed on arm 150 at the intersection thereof with arm160.

The opposite end of the actuating arm 160 is slotted at I 164 to receivea pin 166 connected to a distributing arm or lever 168 locatedintermediate the actuating arm 160 and the valving element 134 whereinlever 168 has one of its ends 170 rotatably supported on the screwelement 136 by a needle bearing 172 carried by arm end 170. In theillustrated embodiment, the terminus of the bent end 156 of swivel arm150 is connected to one end of an elongated spring element 174 havingthe opposite end thereof connected to the outer'end of the pin 166 ondistributor arm 168 for producing a snap-action of arm 168 when thespring passes to one or the other side of the center axis of pivot screw136.

The actuating arm 160 is constructed of a lightweight plastic materialhaving .a low coefficient of friction, for example, Delrin, wherebyfrictional losses between it and swivel arm 150 are minimized.Accordingly, upon movement of the crank arm 146 as it engages theshoulder 88, the bent end 156 of swivel arm 150 will oscillate about theaxis of the end 148 thereof to move the actuating arm 160 in a limitedrotative path about the pivot point thereof to shift the pin 166 alongwith the intermediate distributor arm or lever 168 in a limited rotativepath about the pivot point defined by the needle bearing 172 on screw138. Upon such limited rotative movement of the distributing arm 168, atab portion 178 depending therefrom alternately engages spaced surfaces180, 182 located in the outer face of the valving element 134 on eitherside thereof with the snap movement of the distributing arm 168 producedby spring element 174 producing a highly responsive selecting action.

In the illustrated embodiment a semicircular spring element 184connected between an outwardly directed portion 186 on the pivoted endof valving element 134 and a pin 188 fixedly secured to the housingportion 60 radially inwardly of the valving element 134 produces snapaction movements of valving element 134 as it begins to be moved bydepending tab 178 on distributing arm 168 sutficiently to shift spring184 into opposite off-center positions.

In the improved distributing valve arrangement, the use of lightweight,low coefiicient of friction components including elements of theabove-described type along with 7 the shape of ports 126, 127, 128assures that the assembly will be quickly responsive to the limitedactuating force produced by the engagement of shoulder 88 with crank arm146, and, furthermore, the arrangement of springs 174, 184 in the systemwill produce a rapid shift of the valving element 134 into its operatingpositions. This arrangement along with the illustrated lever armarrangement discussed above produces an actuating assembly havingrelatively low inertial characteristic and, hence, the limited motiveforce of the diaphragm 78 will not be substantially dissipated inactuating the selector valve into its operating positions. In order toprotect the operative parts of the valve assembly 125 a cap 190 bearinga tubular extension 192 thereon communicating the interior thereof withatmosphere is arranged to cover said operative parts. More particularly,cap 190 is secured to the end face of housing portion 60 by studs 194and an annular gasket 195 fits between portion 60 and the edge of cap190 to prevent the entrance of foreign matter thereacross.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. In combination, a pump housing having a first portion and a secondportion joined to said first portion to form a chamber, a flexiblediaphragm extending transversely within said chamber and having theouter periphery there of in sealing engagement with the juncture of saidhousing portions for dividing said chamber into two compartments, eachof said housing portions including cylinder means disposed on oppositesides of said diaphragm, one of said cylinder means being of a greaterdiameter than the other of said cylinder means, piston means in each ofsaid cylinder means, piston rod means connecting said piston meanshaving a portion thereon sealingly connected to said diaphragm means tobe reciprocated thereby along with said piston means in said cylindermeans, means forming an axial passageway directed through said pistonrod means for intercommunicating said cylinder means, means forming aninlet passageway through one of said piston means for communicating oneof said compartments with one of said cylinder means, first valve meanssupported by said one of said piston means for selectively opening andclosing said inlet passageway in said one of said piston means uponreciprocation of said piston rod means whereby air is drawn from saidone of said compartments and discharged into said axial passageway,second valve means in said axial passageway providing the dual functionof a discharge valve from said large diameter cylinder means and aninlet valve for the other cylinder means, means forming ports in saidhousing for communicating each of said compartments to atmosphericpressure, means forming an additional port in said housing adapted to beconnected to a subatmospheric source of pressure, and third valve meansactuated by reciprocal movement of said piston rod means for alternatelyconnecting said additional port with one of said compartment ports whileleaving the other. port exposed to atmosphere to effect a pressuredifferential across said diaphragm for producing the abovementionedreciprocation of said piston means in said cylinder means to obtain atwo-stage compression of fluid.

2. In the combination of claim 1, said first valve means for controllingcommunication between said pumping compartment and said first cylinderincluding an annular disc of flexible material connected at the innerperiphery there- I of to said one of said piston means to be directedradially outwardly to overlie the end of said large diameter end portionso as to close the inlet passageway therethrough, said annular discflexing upon reciprocation of said one of said piston means outwardly ofsaid large diameter cylinder means to open said inlet passageway andoperable to flex in a direction to close said inlet passageway uponopposite reciprocation.

3. In the combination of claim 1, an annular sealing elementon the outerperiphery of each of said piston means for slidably sealingly engagingthe inner surface of said cylinder means, an annular washer elementspaced from said sealing element on the outer periphery of said pistonmeans, and lubricating means impregnating said washer element forreducing friction losses between piston means and cylinder means duringrelative movement therebetween.

4. In combination, a pump housing a first portion and a second portionjoined to said first portion for forming a chamber therebetween, adiaphragm located within said chamber extending transversely thereofhaving the outer periphery thereof held in sealing engagement betweensaid first and second portions at the juncture thereof for dividing saidchamber into two compartments, an elongated piston rod extending throughsaid diaphragm, a first cylinder formed in said first housing portion inaxial alignment with said piston rodfor supporting one end thereof forsliding engagement therewith, a sec-0nd cylinder formed in said secondhousing portion forsupporting an enlarged diameter opposite endportionon said piston rod in sliding engagement therewith, means forconnecting said diaphragm to said piston rod, means forming a port ineach of said housing portions for connecting each of said pumpingcompartments to a source of atmospheric pressure, means forming anadditional port in said housing adapted to be connected with a source ofsubatmospheric pressure, a movable valving element sealingly en gagingsaid housing including passageway means therein for alternatelyconnecting one of said housing portion ports with said additional portwhile leaving the other of said housing ports exposed to atmosphere toeffect a pressure differential across said diaphragm for reciprocatingsaid piston rod, valve actuator means operatively associated with saidpiston rod for moving said valving element into selected positions inresponse to movement of said piston rod to effect a reversal of thepressure differential across said diaphragm by reversing the connectionof said housing ports with said additional port and atmosphere, saidports being trapezoidally shaped to limit the valving movement requiredfor intercommunicating said housing portion ports and said additionalport, said valve actuator means including lever means located interiorlyof one of said compartments to be operatively associated with saidpiston rod, a bent lever element having one end thereof moved through alimited rotative path by said lever means acting on the opposite endthereof, an actuator arm having one end thereof pivotally secured tosaid housing, said actuator arm having an opening therein for receivingsaid one end of said bent lever to operatively connect said actuator armthereto, linkage means including said actuator arm'operable to effect alimited rotational movement of said valving element relative to saidports, first spring means operatively connected between the end of saidbent lever and said linkage for biasing said actuator arm into first andsecond positions, and second spring means operatively connected betweensaid valving element and said housing to snap said valving element intoits selected rotative positions upon rotation of said bent lever by saidlever means.

5. In combination, a pump housing having a first portion and a secondportion joined to said first portion for forming a chamber therebetween,a diaphragm located within said chamber extending transversely thereofhaving the outer periphery thereof held in sealing engagement betweensaid' first and second portions at the juncture thereof for dividingsaid chamber into two compartments, an elongated piston rod extendingthrough said diaphragm, a first cylinder formed in said first housingportion in axial alignment with said piston rod for sup.- porting oneend thereof for sliding engagement therewith, a second cylinder formedin said second housing portion for supporting an enlarged diameteropposite end portion on said piston rod in sliding engagement therewith,means for connecting said diaphragm to said piston rod,

means forming a port in each of said housing portions for connectingeach of said pumping compartments to a source of atmospheric'pressure,means forming an additional port in said housing adapted to be connectedwith a source of subatmospheric pressure, a movable plastic valvingelement sealingly engaging said housing including passageway meanstherein for alternately connecting one of said housing portion portswith said additional port while leaving the other of said housing portsexposed to atmosphere to effect a pressure differential across saiddiaphragm for reciprocating said piston rod, valve actuat-or meansoperatively associated with said piston rod for moving said valvingelement into selected positions in response to movement of said pistonrod to effect a reversal of the pressure differential across saiddiaphragm by reversing the connection of said housing ports with saidadditional port and atmosphere, said plastic valving element reducingfriction losses during pumping and including a passageway therein forintercommunicating said housing portion ports and said additional port,said valve actuator means including a crank arm located interiorly ofone of said compartments to be operatively associated with said pistonrod, a bent lever element having a hemispherical portion on one endthereof moved through a limited rotative path by said crank arm actingon the opposite end thereof, an actuator arm having one end thereofpivotally secured to said housing, said actuator arm having an openingtherein for receiving the hemispherical portion of said bent lever tooperatively connect said actuator arm thereto, linkage means includingsaid actuator arm operable to effect a limited rotational movement ofsaid valving element relative to said ports, first spring meansoperatively connected between the end of said bent lever and saidlinkage means for biasing said actuator arm into first and secondpositions, and second spring means operatively connected between saidvalving element and said housing to snap said valving element into itsselected rotative positions upon rotation of said bent lever by saidcrank arm.

6. In the combination of claim 5, said actuator arm being constructed ofa low coefiicient of friction plastic material for reducing noisetransmission and for improving valve actuator means responsiveness byreducing inertia therein.

References Cited by the Examiner UNITED STATES PATENTS 426,762 4/1890Brookmire 18919 3,148,825 9/ 1964- De Hofi 123052 3,151,804 10/ 1964 LaFlame 2305 2 3,151,805 10/ 1964 Pribonic 23052 ROBERT M. WALKER, PrimaryExaminer.

1. IN COMBINATION, A PUMP HOUSING HAVING A FIRST PORTION AND A SECONDPORTION JOINED TO SAID FIRST PORTION TO FORM A CHAMBER, A FLEXIBLEDIAPHRAGM EXTENDING TRANSVERSELY WITHIN SAID CHAMBER AND HAVING THEOUTER PERIPHERY THEREOF IN SEALING ENGAGEMENT WITH THE JUNCTURE OF SAIDHOUSING PORTIONS FOR DIVIDING SAID CHAMBER INTO TWO COMPARTMENTS, EACHOF SAID HOUSING PORTIONS INCLUDING CYLINDRER MEANS DISPOSED ON OPPOSITESIDES OF SAID DIAPHRAGM, ONE OF SAID CYLINDER MEANS BEING OF A GREATERDIAMETER THAN THE OTHER OF SAID CYLINDER MEANS, PISTON MEANS IN EACH OFSAID CYLINDER MEANS, PISTON ROD MEANS CONNECTING SAID PISTON MEANSHAVING A PORTION THEREON SEALINGLY CONNECTED TO SAID DIAPHRAGM MEANS TOBE RECIPROCATED THEREBY ALONG WITH SAID PISTON MEANS IN SAID CYLINDERMEANS, MEANS FORMING AN AXIAL PASSAGEWAY DIRECTED THROUGH SAID PISTONROD MEANS FOR INTERCOMMUNICATING SAID CYLINDER MEANS, MEANS FORMING ANINLET PASSAGEWAY THROUGH ONE OF SAID PISTON MEANS FOR COMMUNICATING ONEOF SAID COMPARTMENTS WITH ONE OF SAID CYLINDER MEANS, FIRST VALVE MEANSSUPPORTED BY SAID ONE OF SAID PISTON MEANS FOR SELECTIVELY OPENING ANDCLOSING SAID INLET PASSAGEWAY IN SAID ONE OF SAID PISTON MEANS UPONRECIPROCATION OF SAID PISTON ROD MEANS WHEREBY AIR IS DRAWN FROM SAIDONE OF SAID COMPARTMENTS AND DISCHARGED INTO SAID AXIAL PASSAGEWAY,SECOND VALVE MEANS IN SAID AXIAL PASSAGEWAY PROVIDING THE DUAL FUNCTIONOF A DISCHARGE VALVE FROM SAID LARGE DIAMETER CYLINDER MEANS AND ININLET VALVE FOR THE OTHER CYLINDER MEANS, MEANS FORMING PORTS IN SAIDHOUSING FOR COMMUNICATING EACH OF SAID COMPARTMENTS TO ATMOSPHERICPRESSURE, MEANS FORMING AN ADDITIONAL PORT IN SAID HOUSING ADAPTED TO BECONNECTED TO A SUBATMOSPHERIC SOURCE OF PRESSURE, AND THIRD VALVE MEANSACTUATED BY RECIPROCAL MOVEMENT OF SAID PISTON ROD MEANS FOR ALTERNATELYCONNECTING SAID ADDITIONAL PORT WITH ONE OF SAID COMPARTMENT PORTS WHILELEAVING THE OTHER PORT EXPOSED TO ATMOSPHERE TO EFFECT A PRESSUREDIFFERENTIAL ACROSS SAID DIAPHRAGM FOR PRODUCING THE ABOVE MENTIONEDRECIRPOCATION OF SAID PISTON MEANS IN SAID CYLINDER MEANS TO OBTAIN ATWO-STAGE COMPRESSION OF FLUID.